Membrane-related thermo-osmotic effect as measured by medium conductivity in isotonic cell suspensions

Changes in temperature result in changes in cell-membrane permeability for water and solutes. At isotonic conditions this thermo-osmotic effect is relatively small and remains indistinguishable by the ordinary impedance methods. The thermo-osmotic effect can be investigated in cell suspensions in the beta-dispersion region (high-frequency electric field with an intensity of 100-300 V/cm, peak-to-peak). The current through the cell suspension of Nicotiana tabacum protoplasts (or human erythrocytes) is a nonlinear function of temperature jump and/or cooling rate. In experiments carried out in a microchamber with thermostatted electrodes at supra-zero temperatures quantitative data were obtained for the thermo-osmotic phenomenon in cell suspension as well as for individual cells.